1. School of Life Sciences, Tianjin University, 92 Weijin Road,
Nankai District, Tianjin 300072, P. R. China
2. Key Laboratory of Analytical Science and Technology of Hebei Province, College of Chemistry and Environmental Science, Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of the Ministry of Education, Hebei University, Baoding 071002, P. R. China